This invention relates to an electrophotographic photoreceptor, an electrophotographic image forming method, an electrophotographic image forming apparatus and a processing cartridge.
It has been strongly demanded to inhibit wearing caused by friction with a cleaning blade for raising the durability of an organic photoreceptor. A technique such as providing a strong protective layer on the surface of the photoreceptor has been tried for such the purpose. For example, Japanese Patent Publication Open for Public Inspection, hereinafter referred to JP O.P.I., Nos. 9-190004 and 10-251277 each describe a photoreceptor in which a siloxane resin excellent in the strength is used as the surface layer.
However, the surface layer of the siloxane resin tends to be stripped off since large torque is caused by the cleaning blade under a high temperature and high humid condition.
It is effective to reduce the frictional force between the cleaning blade and the surface layer by reducing the surface energy of the surface layer for preventing the stripping off of the surface layer. For example, JP O.P.I. No. 10-83094 describes a method using a surface layer having a low surface energy such as one having a contact angle with water of not less than 900. However, it is found that the problem cannot be solved only by the introduction of a fluorine atom into the silane compound described in the foregoing publications since the blade torque is depended not only on the chemical affinity but the factor relating to the viscoelastic property of the surface layer.
The object of the invention is to provide an electrophotographic photoreceptor, an electrophotographic image forming method, an electrophotographic image forming apparatus and a processing cartridge by which the cleaning blade torque is effectively reduced and an apparent image flowing occurred under a high temperature and high humid condition is not occurred, which is a problem relating the hard coat of the photoreceptor.
As a result of studying by the inventors for solving such the problem, it has been found that the torque caused by the blade can be effectively reduced and a desirable property without formation of the considerable flowed image under the high temperature and high humid condition which is the problem to be solved in the hard coat of the photoreceptor can be obtained by the use of the surface layer of the photoreceptor having both of a siloxane cross-linked layer mainly composed of a bifunctional silane compound and a structural unit having an electron transportation ability in stead of a trifunctional silane compound mainly used in the known silicone-type hard coat.
The object of the invention can be attained by the following construction.
An electrophotographic photoreceptor having a resin layer comprising a siloxane resin formed by hardening a compound represented by Formula 1, 2 and 3, or a hydrolyzed product which has a structural unit having a charge transportation ability, wherein a ratio M1/M2 of the sum of the amount in moles M1 of the compound represented by Formula 1 and that represented by Formula 2 to the amount in moles of the compound represented by Formula 3 is within the range of from 0.01 to 1.
The resin layer preferably contains fine particles having a volume average diameter of from 1 nm to 10 Wm.
The resin layer is preferably the surface layer of the photoreceptor.
The siloxane resin is preferably a siloxane resin containing a structure represented by Formula 4.
The photoreceptor preferably has an interlayer between a cylindrical electroconductive substrate and a photosensitive layer.
The resin layer preferably contains an antioxidant.
The photoreceptor is preferably used in an electrophotographic image forming method including processes for electrostatic charging, imagewise exposing, developing and cleaning.
The photoreceptor is preferably used in an electrophotographic image forming apparatus having processes for electrostatic charging, imagewise exposing, developing and cleaning.
It is preferable that the photoreceptor is combined with any one of a charging means, an imagewise exposing means, a developing means and a cleaning means to form an unitized processing cartridge to be used in an electrophotographic image forming apparatus comprising the photoreceptor, a charging means, an imagewise exposing means, a developing means and a cleaning means, and the cartridge is designed for capable of freely inserted into the electrophotographic image forming apparatus.